Operating upon strips of thin material

ABSTRACT

A rotary slitter, for slitting a strip of thin material into narrower ribbons and establishing the speed of travel of those ribbons, is provided with output-disengaging means of dynamic nature, moved by and with the elements of the slitter, enabling the minimization of tension on the exiting ribbons. A pair of ribbon-engaging rollers, driven at a peripheral speed slightly greater than the speed of travel of the ribbons, receives the ribbons from the slitter in side-by-side relationship and under slight tension. From the rollers the ribbons may optionally pass to an anvil member with which a cutter cooperates to cut the ribbons into discrete small pieces.

1451 Mar.21, 1972 United States Patent Ruschmann [54] OPERATING IIPONSTRIPS OF THIN PATENTEI] MAR 21 i972 SHEET 1 UF 2 /N VEN 70A HENRY ERUSCHMA/VN A T TOPNE Y OPERATING UPON STRIPS OlF THIN MATERIAL Thisinvention relates to operating upon strips of thin material, typicallyof foil, and more particularly to continuously operating apparatus forsubdividing such strips into narrower ribbons or into discrete smallpieces. By the term foil I refer to material either of metal or ofplastic, plated or unplated, single-ply or laminated, of a thicknesswhich may vary from a small fraction of a mil up to many mils.

For the widthwise subdivision of such strips there is well known arotary slitter typically made up of two interrelated elements eachcomprising an assembly, on a respective shaft, of concentric discsspaced from each other by circular spacing means of smaller radius, thetwo shafts being appropriately journaled so that the discs of oneelement extend slightly between the discs of the other, the shafts beingsubjected to rotation, in opposite directions at similar peripheralspeeds, which draws the foil strip into the crevice at which the slightoverlap of the discs begins and there effects the slitting of the strip.From there each ribbon must pass on through the region of overlap; asthey pass the plane containing the axes of the slitter elements,alternate ones of the ribbons are disposed between discs of one elementand the intervening ones are disposed between discs of the otherelement. The ribbons pass on to exit from the slitter beyond the regionof overlap; in so passing, however, each ribbon as a result of frictionbetween its edges and the respective discs between which it was formedis prone to remain between those discs-a tendency which unless overcomefrustrates the exiting of the ribbons from the slitter. To rely solelyon the exertion of tension on each output ribbon is usually quiteimpractical in view of the magnitude of the tension required, andrecourse has therefore been had to one or another form of stationarydisengaging means extending into the spaces formed between the discs ofeach element. Such means, however, when taken in their entirety (i.e.,with mountings etc., which their incorporation necessitates) normallyoccupy principally space not occupied by the rotary elements of theslitter proper, they interfere with accessibility for start-up andsimilar purposes, and their dependability leaves something to bedesired; furthermore they entail sliding friction of the ribbon surfacesagainst them.

It is desirable that the ribbon-disengaging action be accomplished bydynamic means-eg., which are not stationary but instead move with theelements of the slitter-which moreover are principally contained withinspace which is in any event occupied by the slitters rotary elements,which pose no interference with accessibility, and whose action is ofenhanced dependability; furthermore they entail essentially no slidingfriction of the ribbon surfaces against them. With these dynamic meansthe tension required on the output ribbons becomes a slight tensiononly. This feature, which is advantageous in any case, is especially soin the case of relatively extensible materials (such as Mylar) and smallthicknesses of the strip (such for example as 0.0002 inch), in order toavoid significant stretching (which is always undesirable, and isruinous to appearance in the case of plated foils).

For some purposes it is acceptable that the output ribbons be deliveredfrom a slitter to subsequent functions-eg., cutting, reeling on a commonreel, or other function-in sideby-side relationship; for other purposesthe ribbons are to be delivered to individual destinations-eg., reeledon individual spools-each of which may for its own purposes provide sometension on its respective ribbon. In either case I have foundadvantageous the collection of both the alternate and interveningribbons from the slitter in side-by-side relationship and under lighttension; this may be done by a ribbon-contacting roller assemblydownstream from the slitter, and means for imparting to that assemblyrotation at a peripheral speed at least slightly greater than the speedor ribbon travel.

A particular such subsequent function may be the cutting of each ribboninto discrete small pieces, such as slivers. In my prior U.S. Pat. No.3,156,283 I disclosed a method and apparatus for the production ofslivers in which a rotary slitter was used at a final stage. There are,however, requirementsin respect of nature of the foil material to becut, dimensions of the final product, or the like-for which I have foundpreferable an initial slitting of the strip into ribbons followed by thecutting of the slivers from those ribbons. For this purpose the exitribbons may pass directly from such a ribbontensioning means as isreferred to in the last preceding paragraph to an anvil member withwhich a cutter (for example, a rotary cutter of the general nature ofone of the cutters disclosed, for a quite different purpose, in U.S.Pat. No. 3,491,636 to Braun) cooperates to sever the slivers form theribbons.

Important objects of the invention have been made apparent by theforegoing introduction. Allied and other objects will more fully appearfrom the following description andthe appended claims.

An important aspect of the invention, then, concerns a rotary slitterhaving two rotary slitter elements whose axes are parallel and each ofwhich comprises a respective series of spaced discs centered on its axisand intertting in slightly overlapping relationship between the discs ofthe other element, for slitting the strip into and establishing thespeed of travel of a plurality of narrow foil ribbons of which, as theypass the plane containing said axes, alternate ones are disposed betweendiscs of one element and the intervening ones are disposed between discsof the other element. The slitter is provided with dynamicribbon-disengaging means, comprising members moved by and with theelements, initially effective on each of the foil ribbons substantiallyat the axescontaning plane. With the foregoing there are employed means,including a ribbon-contacting roller assembly downstream from theslitter and means for imparting thereto rotation at a peripheral speedat least slightly greater than the speed of ribbon travel, forcollecting both said alternate and said intervening foil ribbons fromthe slitter in side-by-side relationship and under light tension.

In another aspect of the invention there are combined, with the subjectmatter of the immediately preceding paragraph, an anvil memberdownstream from and onto which the ribbons pass in side-by-siderelationship from the roller assembly, and a cutter cooperating with theanvil member to cut the ribbons into discrete small pieces. The ribbonsmay pass without longitudinal tension thereof from the pair of rollersto the line of interaction between cutter and anvil member, and meansmay be provided between the pair of rollers and that line formaintaining direct the path of the ribbons therebetween; that line maybe relatively close to the pair of rollers thereby to minimize thedistance of such passage.

In the detailed description of the invention hereinafter set forthreference is had to the accompanying drawings, in which F IG. 1 is avertical cross-sectional view taken longitudinally through a typicalapparatus according to the invention;

FIG. 2 is a vertical view of the rotary slitter alone, taken lookingupstream (the line 1-1 in FIG. 2 indicating the plane along which FIG. 1is taken);

FIG. 3 is a plan view of portions of the apparatus downstream of the`slitter and showing the ribbons formed by the slitter; and

FIG. 4 is a vertical cross-sectional view taken along the line 4-4 ofFIG. 3.

FIG. l shows the apparatus with a strip l entering it from the left. Inview of the thin nature of that strip it will be understood that itsthickness-and that of the ribbons 4 and 3 into which it is subdivided bythe slitter-as appearing in FIG. l has, in the interest of clarity ofillustration, been greatly exaggerated. The strip may be continuouslydrawn from a supply roll (not shown) diagonally upwardly onto a smoothtable 15; in its passage along that table the strip may slide under atransverse bar or plate 16 whose extremities may be loosely retained bystationary pins 17 and which has a smooth bottom surface resting on themoving strip. The table 15 may extend to within a short distance of thedisc-overlap region of a rotary slitter 20, through which that strippasses and which slits it into a number of narrower ribbons (best seenin FIG. 3), alternate ones of which are designated as 4 and in theintervening ones as 3.

The slitter 20, in accordance with preferred known practice, maycomprise interrelated lower and upper elements each comprising anassembly of concentric discs and circular spacing means on a respectiveshaft. The upper element,`

whose shaft is 22, may comprise an alternation of hardened discs 24 withspacing means 26 (which preferably are also hardened) of smaller radiusbut similar thickness; the lower element, whose shaft is 21, maycomprise an alternation of corresponding spacing means 25 andcorresponding discs 23-and may if desired include at each end a disc 29of enlarged radius to provide lateral guidance for the entering strip 1.The shafts 21 and 22, which are journaled in suitable fixed bearings(not shown), are appropriately positioned relative to each other tobring the uppermost peripheral portions of the discs 23 between thelowermost peripheral portions of the discs 24; the amount of overlap,which is preferably small, has been exaggerated in the drawings forclarity of illustration.

Each of the shafts 2l and 22 may be coupled to a drive motor throughsuitable positive-coupling means (schemativ cally indicated at 19) sothat they execute oppositely directed rotations (21 clockwise, 22counterclockwise, as viewed in FIG. 1) at identical peripheral speeds.lt is such rotation of those shafts which draws thestrip l onto andalong the table l5, and which determines the speed of travel of thestrip through the apparatus. A

The cutting action of the slitter and thus the formation of the ribbons4 and 3 from the strip 1 of course takes place as that strip enters theregion of overlap of the discs 23 and 24- i.e., slightly upstream fromthe vertical plane containing the axes of the slitter elements. At thatvertical plane the ribbons 4 will be in contact with the bottomperipheries of respective discs 24, while the intervening ribbons 3 willbe in contact with the top peripheries of respective discs 23.

In each of the two elements of the slitter the disengaging meansaccording to the invention may comprise annular members-designated as 27in the lower element and as 28 in the upper-intervening between that.elements successive discs, each in surrounding relationship to arespective one of that elements spacing means; they are at leastslightly thinner than the spacing discs, so that they intervene freelybetween the respective discs. In each element those annular members havean external radius greater than that of the discs, and an excess ofexternal over internal radius slightly less than the excess of discradius ever spacing-means radius.

Means (seen in FIG. 1) are provided upstream from each slitter elementfor causing the centers of that elements annular members 27 or 28 to beslightly more downstream than the axis of that slitter element. Such ameans for the upper element may be a roller 32 appropriately journaledat a level somewhat above the axis of the upper element; for the lowerelement it may be a roller 31 appropriately journaled at a levelsomewhat below the axis of the lower element. In the case of the upperelement gravity causes an outer-peripheral point on each annular member28 to rest or bear against the top of the respective ribbon 3; theup-and-downstream position of the roller 32 may be such that the innerperiphery of that annular member 28 will just or almost contact therespective spacing means 26 at a point on the latter (such as B in FIG.l) somewhat upstream from the plane containing the axes of the slitterelements. In the case of the lower element gravity causes aninner-peripheral point on each annular member 27 to rest or bear againstan upper-peripheral point on the respective spacing means 25; theup-and-downstream position of the roller 3l may be such as to cause thatupper spacingmeans point to be a point (such as A in FIG. 1) somewhatupstream from the plane of the slitter-element axes, and to cause anouter-peripheral point on that annular member just or almost to contactthe bottom of the respective ribbon 4.

Optionally in the case of the lower element there may be employed anadditional roller 33, appropriately journaled below the axis of thatelement and somewhat downstream from the plane containing theslitter-element axes, against lwhich an outer-peripheral point on eachof the annular members 27 may bear. When the roller 33 is employed it isthat roller and the roller 31, taken together, which determine the exactpositions of the annular members 27; by suitable adjustments of thepositions of the two the above-mentioned bearing of each of thoseannular members against the spacing means 25 may be relieved, and at thesame time the above-mentioned contacting of the respective ribbons 4 bythose annular members may be more accurately controlled.

While the annular members 27 and 28 are free with respect to the otherportions of their respective slitter elements, they nevertheless engagein rotation along with those elements, obviously however being alsomeanwhile forced continuously to shift radially with respect to thoserespective elements. By the annular-member rotation the rollers 3l and32 (and 33 if em ployed) are rotated in the directions indicated byarrows in FIG. l.

As a result of the annular-membertodisc relationships set forth in thelast few paragraphs the radial distance by which the outer periphery ofeach annular member 28 is inset from the peripheries of the adjacentdiscs 24, which distance was at a maximum at a point in radial alignmentwith B, progressively diminishes downstream from that point, beingalready diminished at the plane containing the slitter-element axes andreaching zero at a position (such as that of D in FIG. l) not fardistant downstream from the region of disc overlap; likewise the radialdistance by which the outer periphery of each annular member 27 is insetfrom the peripheries of the adjacent discs 23, which distance was at amaximum at a point in radial alignment with A, progressively diminishesdownstream from that point, being already diminished at theaxes-containing plane and reaching zero at a position (such as that of CIN FIG. 1) not far downstream from the region of disc overlap. Thus inpassing even infinite similarly downstream from the axes-containingplane each ribbon 3 is being progressively displaced by the respectiveannular member 28 away from the axis of the upper element, so thatstatic friction between it and the discs 24 between which it wasformed-which tends to cause it to remain at a constant radial distancefrom the upper element axis-is at once overcome; a correspondingprogressive displacement is effected on each ribbon 4 by the respectiveannular element 27, with a corresponding result. It may be that thefreedom with which the annular members 27 and 28 are carried by theirrespective slitter elements contributes in some additionalway or ways tothe effectiveness of the arrangement. In any event the net operationaleffects are high reliability of operation, essential elimination offriction against the surfaces of the ribbons, and the significantreduction of required exit tension introductorily referred to above.

For the provision of the appropriate slight exit tension-or of more werethere to be employed lesseffective-ribbon-disengaging means-I provide aribbon-tensioning means 40 acting in common on all the side-by-sdeexiting ribbons. Between the slitter 20 and the ribbon-tensioning means40 the tensioned ribbons may slide along the top surface of a table 35,whose upstream portion may be a plate 34 extending to within a shortdistance of the region of slitter-disc overlap. The top of portion 34may be in horizontal alignment with the top peripheries of the discs 23,thus affording an opportunity for the ribbons 3 to leave the slitter ina quite horizontal path; to accommodate to the slightly inclined pathwhich the ribbons 4 must take (whose inclination has sufferedexaggeration in F IG. l in the interest of clarity of illustration) themarginal upstream surface of portion 34 may be slightly rounded. Intheir passage along the table 35 the ribbons may if desired slide undera smooth-bottomed transverse bar 36 whose extremities are looselyretained by stationary pins 37; the bar 36, if employed, is preferablyof light material so as not to contribute appreciably to theribbon-tensioning requirement.

The ribbon-tensioning means 40 may comprise a ribboncontacting rollerassembly made up of a pair of ribbon-engaging rollers 4l and 42 betweenwhich the ribbons pass in sideby-side relationship, and into closeproximity to which the table 35 may extend. The rollers are biasedtoward each other so as to grip the ribbons. They are appropriatelydriven at a peripheral speed slightly greater than the linear speed oftravel of the ribbons established by the slitter; thus there is at leastslight slippage of each ribbon relative to the rollers, accompanied by atensioning of each ribbon in its extent between slitter and rollers. Thesurface of at least one and preferably of each of the rollers isresilient, thereby to enhance the independence of the action of the pairof rollers on each ribbon from its action on the other ribbons;desirably that surface is also friction-prone but wear-resistant, andNeoprene rubber has been found suitable for the purpose.

In the drawings the lower roller is 41, its surface layer (e. g., ofNeoprene rubber) is 43, and its terminal shafts are 45; the upper rolleris 42, its surface layer 44, and its terminal shafts 46. For thejournaling of those shafts there may be provided at each side of theapparatus an appropriate fixed standard such as illustrated at one sideas 50; the shafts 45 may be journaled in those standards. In its upperportion each of those standards may have formed into spaced bifurcations51 and 52, surmounted by a crossmember 53. Between the bifurcations ofeach standard there may float a block 54 into which the respective shaft46 is -journaled; a screw 58 may extend downwardly through thatstandards crossmember 53 carrying at its bottom an inverted cup 57, andbetween the upper inner surface of that cup and the bottom ofa recess 55in the top of the block 54 therebelow there may be compressed a spring56 whose effect is to bias the roller 42 against the roller 41. With anygiven roller surfaces the tension exerted by the tensioning means 40 onthe ribbons exiting from'the slitter 20 may be regulated by the choiceof roller speed and the adjustment of the roller bias-the latter ofcourse by adjustment of the screws 58.

At a common end of the rollers 41-42 their shafts 45 and 46 mayrespectively carry intermeshing identical gears 47 and 48 commanding therotation of the rollers (4l clockwise, 42 counterclockwise, as viewed inFIG. 1) at identical peripheral speeds. The shaft of one of the rollers(e.g., that of the lower roller 41) may be coupled to the drive motor 10through suitable positive-coupling means (schematically indicated at 49in Flg. l) chosen to result in the rotation of the rollers at theperipheral speeds above referred to. Vertically the rollers 41-42 may bepositioned so that the bottoms of the ribbons 4 and 3 passing betweenthem are at the level of the top of the table 35 above-mentioned.

From the pair of rollers 41-42 the ribbons 4 and 3 may of course pass onin any desired paths to any desired destinations, which may for examplebe individual to the respective ribbons. On the other hand there arevarious end-product requirements for which advantage may be taken of thepresentation of the ribbons in side-by-side relationship from that pairof rollers. One such end-product requirements is for small discretepieces to be cut from the ribbons-by way of nonlimitative but specificexample, slivers of stainless-steel foil of about 0.002 inch thickness,each sliver being about 0.004 inch width and about 0.080 inch length,that length being conveniently the width of the ribbon. For suchpurposes it is highly convenient that the ribbons pass, still inside-by-side relationship, from the pair of rollers 41-42 onto an anvilmember which is provided downstream form the rollers and with which asuitable cutter cooperates to cut the ribbons into the discrete smallpieces-eg., the slivers just mentioned.

Such an anvil member is shown in the drawings as 60. Its top may lie inthe plane of the tops of plate 34 and table 35. The top downstreamportion 61 of the anvil member 60 may be formed as an insert removablefrom the rest of that member, and the downstream face of the portion 6lmay be inclined so as to render acute its angle of intersection with thetop surface of that portion-which intersection, lying on the locus ofmovement of the cutting edges of the cutter referred to in the nextsucceeding paragraph, forms the line of interaction between cutter andanvil member. To minimize the frequency of required resharpenings of theportion 61 at that line the portion 61 may be formed of hard andabrasion-resistant material such as tungsten carbide.

The cutter 70 may for example be, and for such an end product as theslivers mentioned above preferably is, a rotary cutter. lts shaft 71 maybe appropriately journaled, for example at the level of the top of60-61, to bring the locus of the cutters teeth into the above-describedrelationship to 61, and may be coupled through suitablepositive-coupling means (schematically indicated at 69 in FIG. l) toresult in rotation of the cutter (counterclockwise as viewed in FIG. 1)at a peripheral speed appropriate to the desired dimension of the finalproduct taken in the direction which is longitudinal ofthe ribbons. Ifthat product is to be a sliver of which the width of the ribbon will bethe length, that it is of course the width of the sliver which will beestablished by the cutter-rotation speed. That final product will ofcourse be discharged downwardly by the cutter, and may be collectedbelow the cutter by any suitable means (not shown).

In this organization, in which the ribbons pass without longitudinaltension from the pair of rollers 4h42 to the line of interaction betweencutter and anvil, it is desirable to provide means between the rollerand that line for maintaining direct the path of the ribbonstherebetween. Such a means may for example be a smooth-bottomedtransverse bar 66, typically of metal, resting on top of the ribbons andunder which they slide in their passage along the top of 60-61. Theextremities of the bar 66 may be loosely retained by stationary pins 68;preferably the holes in that bar accommodating those pins will be linedwith nonmetallic inserts 67 such as of Bakelite.

,It will of course be appreciated that the invention is appropriate notonly to operation upon materials of a wide range of thicknesses, asintroductorily pointed out, but also to the production of ribbons of awide variety of widths, determined of course by the thickness of thediscs and spacing means in the slitter 20. (In the drawings thatthickness, when taken relatively to other dimensions in the drawings,may be considered as having been chosen, arbitrarily, for a ribbon widthof the very general order of 0.125 inch.) Of course likewise when theribbons 4 and 3 are cut into discrete pieces the dimensions of thosepieces longitudinal of the ribbons may be widely varied by the geometry,nature and speed of the cutter.

Whilethe entering strip l has been shown as a single one, it will ofcourse be understood that two or more strips, in sideby-siderelationship and drawn from respective rolls, may equally well beaccommodated; thus for example I have with highly satisfactory resultsemployed the disclosed apparatus, with appropriately wide slitter andappropriately long rollers 41-42 and anvil member 60 and cutter 70, tooperate on two strips, in such relationship, each of 4 inch width, forthe production of the above-described slivers therefrom.

While I have disclosed my invention in terms of a particular embodimentthereof, I intend thereby no unnecessary limitations. Modications inmany respects will be suggested by my disclosure to those skilled in theart, and such modifications will not necessarily constitute departuresfrom the spirit of the invention or from its scope, which I undertake todefine in the following claims.

I claim:

1. A machine for continuous operation upon a strip of foil comprising,in combination, (l) slitter means, having two rov tary elements whoseaxes are parallel and each of which comprises a respective series ofspaced discs centered on its axis and intertting in slightly overlappingrelationship between the discs of the other element, for slitting thestrip into and establishing the speed of travel of a plurality of narrowfoil ribbons of which, as they pass the plane containing said axes,alternate ones are disposed between discs of one element and theintervening ones are disposed between discs of the other element; (2)dynamic ribbon-disengaging means, comprising members carried by andmoved with said elements, initially effective on each of said foilribbons substantially at said axescontaining plane; and (3) means,including a ribbon-contacting roller assembly downstream from theslitter means and means for imparting thereto rotation at a peripheralspeed at least slightly greater than said speed of ribbon travel, forcollecting both said alternate ancll said intervening foil ribbons fromthe slitter means in sidebyside relationship and under light tension.

2. The subject matter claims in claim l wherein said collecting meansfurther includes, upstream from said roller assembly, a surface ontowhich there pass, in two respective planes only slightly inclinedrelative to each other, the ribbons from between the discs of one ofsaid elements and the ribbons from between the discs of the otherelement.

3. The combination, withv the subject matter claimed in claim 1, of ananvil member downstream from and onto which

1. A machine for continuous operation upon a strip of foil comprising,in combination, (1) slitter means, having two rotary elements whose axesare parallel and each of which comprises a respective series of spaceddiscs centered on its axis and interfitting in slightly overlappingrelationship between the discs of the other element, for slitting thestrip into and establishing the speed of travel of a plurality of narrowfoil ribbons of which, as they pass the plane containing said axes,alternate ones are disposed between discs of one element and theintervening ones are disposed between discs of the other element; (2)dynamic ribbon-disengaging means, comprising members carried by andmoved with said elements, initially effective on each of said foilribbons substantially at said axes-containing plane; and (3) means,including a ribbon-contacting roller assembly downstream from theslitter means and means for imparting thereto rotation at a peripheralspeed at least slightly greater than said speed of ribbon travel, forcollecting both said alternate and said intervening foil ribbons fromthe slitter means in sideby-side relationship and under light tension.2. The subject matter claims in claim 1 wherein said collecting meansfurther iNcludes, upstream from said roller assembly, a surface ontowhich there pass, in two respective planes only slightly inclinedrelative to each other, the ribbons from between the discs of one ofsaid elements and the ribbons from between the discs of the otherelement.
 3. The combination, with the subject matter claimed in claim 1,of an anvil member downstream from and onto which said ribbons pass inside-by-side relationship from said roller assembly, and a cuttercooperating with said anvil member to cut said ribbons into discretesmall pieces.
 4. The subject matter claimed in claim 3 wherein saidribbons pass without longitudinal tension from said roller assembly tothe line of interaction between said cutter and said anvil member,further including means between said roller assembly and said line formaintaining direct the path of said ribbons therebetween.